Ion conductive material, electrolyte including ion conductive material, and methods of forming

ABSTRACT

A solid ion conductive material can include a complex metal halide. The complex metal halide can include at least one alkali metal element. In an embodiment, the solid ion conductive material including the complex metal halide can be a single crystal. In another embodiment, the ion conductive material including the complex metal halide can be a crystalline material having a particular crystallographic orientation. A solid electrolyte can include the ion conductive material including the complex metal halide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority under 35U.S.C. § 120 to U.S. patent application Ser. No. 17/230,908, entitled“ION CONDUCTIVE MATERIAL, ELECTROLYTE INCLUDING ION CONDUCTIVE MATERIAL,AND METHODS OF FORMING,” by Vladimir OUSPENSKI et al., filed Apr. 14,2021, which claims priority under 35 U.S.C. § 119(e) to U.S. ProvisionalPatent Application No. 63/009,901, entitled “ION CONDUCTIVE MATERIAL,ELECTROLYTE INCLUDING ION CONDUCTIVE MATERIAL, AND METHODS OF FORMING,”by Vladimir OUSPENSKI et al., filed Apr. 14, 2020, all of which areassigned to the current assignee hereof and incorporated herein byreference in their entireties for all purposes.

FIELD OF THE DISCLOSURE

The following is directed to a solid ion conductive material,electrolyte including the ion conductive material, and methods offorming the same, and to, in particular, a solid ion conductive materialincluding a complex metal halide, electrolyte including the same, andmethods of forming the same.

DESCRIPTION OF THE RELATED ART

Solid-state lithium batteries, by enabling lithium metal anode, areexpected to provide higher energy densities and faster recharging timesand cause less safety concerns compared to conventional lithium-ionbatteries. Current solid electrolyte materials include oxides, halides,sulfides, fluorides, and solid polymer electrolytes.

Oxide-based materials have been considered safe and possessing goodchemical and electrochemical stability. The synthesis of these compoundsgenerally uses high temperatures that are above 1000-1200° C. Theoxide-based materials are typically dense, rigid, and brittle with ionicconductivity up to 1.0 mS/cm at room temperature (IC_(RT)).

Halide compounds, such as chlorides and bromides, are generally safe andhave good chemical and electrochemical stability, deformability, andplasticity, allowing relatively high compatibility with active electrodematerials. Some Li₃YCl₆ (LYC) and Li₃YBr₆ (LYB) electrolytes havedemonstrated room-temperature ionic conductivity IC_(RT) above 1 mS/cm.Halides are generally hygroscopic and form hydrates or undergohydrolysis upon exposure to moisture. Halide solid electrolytes, such asLYC and LYB, are synthesized by using high-energy ball milling-basedsolid-state synthesis methods. The synthesis possesses challenges formass production applications, further because expensive binary halidereactants and/or high-temperature annealing are used.

Fluorides are very similar to oxides in physical, chemical, andelectrochemical properties, but in general, have IC_(RT) values below 1mS/cm.

Sulfides have relatively high ionic conductivity. For instance, IC_(RT)can be as high as 25 mS/cm while commercially relevant sulfide orthiophosphate solid electrolytes can achieve 2-10 mS/cm. Sulfidematerials are mechanically softer and deformable. However, sulfidematerials tend to have poor electrochemical stability and cause safetyconcerns due to the risk of releasing toxic H₂S gas when accidentallyreacting together with water and heat. Further, high surface areasulfide solid electrolyte powders pose a particularly high H₂S risk dueto their increased reactivity even with ambient humidity.

Solid polymer electrolytes containing lithium salts in general haverelatively low IC_(RT) values and electrochemical stability.

The industry continues to demand improved solid electrolyte materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousfeatures and advantages made apparent to those skilled in the art byreferencing the accompanying drawings.

FIG. 1 includes a flowchart illustrating a process of forming a solidion conductive material according to an embodiment.

FIG. 2 includes a flowchart illustrating a process of forming a solidion conductive material according to another embodiment.

FIG. 3A includes a cross-sectional illustration of a solid ionconductive material according to an embodiment.

FIG. 3B includes an illustration of exemplary crystallographicorientations of the solid ion conductive material of FIG. 3A.

FIG. 4 includes a flowchart illustrating a process of forming a solidion conductive material according to an embodiment.

FIG. 5 includes a cross-sectional illustration of a portion of asolid-state battery according to an embodiment.

Skilled artisans appreciate that elements in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the elements in the figures canbe exaggerated relative to other elements to help improve understandingof embodiments of the invention. The use of the same reference symbolsin different drawings indicates similar or identical items.

DETAILED DESCRIPTION

The following description in combination with the figures is provided toassist in understanding the teachings disclosed herein. The followingdiscussion will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings.

As used herein, the terms “comprises,” “comprising,” “includes”,“including”, “has”, “having,” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of features is notnecessarily limited only to those features but can include otherfeatures not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive-or and not to an exclusive-or. For example,a condition A or B is satisfied by any one of the following: A is true(or present), and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

The use of “a” or “an” is employed to describe elements and componentsdescribed herein. This is done merely for convenience and to give ageneral sense of the scope of the invention. This description should beread to include one or at least one and the singular also includes theplural, or vice versa, unless it is clear that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting.

Embodiments herein relate to a solid ion conductive material including acomplex metal halide, wherein the metal can include at least one alkalimetal element. In an embodiment, the solid ion conductive material caninclude a dopant including ammonium. In another embodiment, the solidion conductive material can include a crystalline material, and inparticular embodiments, oriented crystalline material, such as a singlecrystal having a particular crystallographic orientation or an orientedceramic. The solid ion conductive material can have improved properties,such as purity, bulk ion conductivity, electrochemical stability, or anycombination thereof, compared to conventional metal halide materials. Inembodiments, the solid ion conductive material can be used to form anelectrolyte, an anode, and/or a cathode, or another component of anelectrochemical device. In particular embodiments, the solid ionconductive material can be a suitable component of a solid-state lithiumbattery.

Embodiments relate to methods of forming the ion conductive material.The method can allow the formation of the ion conductive material havingimproved properties, such as purity, ion conductivity, electrochemicalstability, or a combination thereof. The method can also allow theimproved formation of the ion conductive material. The method can besuitable for the massive production of the ion conductive material in acost-efficient manner.

Referring to FIG. 1, a process for forming a solid ion conductivematerial 100 is illustrated.

The process 100 is different from the conventional solid-state synthesisfor forming complex metal halide. The conventional process utilizeshigh-energy ball milling or directly heating the reactants mixture(e.g., simple metal halides) at a temperature near or below the meltingpoints of the metal halides to perform the solid-state reaction. Becausethe probability of reacting individually separated particles in amixture decreases as the reaction proceeds, achieving 100.00% completionof the reaction will theoretically take an infinite amount of time. Itis thus understandable the reaction products resulted from theconventional solid-state synthesis that is based on high energy ballmilling have a higher concentration of impurities, such as a simplemetal halide (e.g., lithium halide and/or yttrium halide), due toincomplete reactions of the simple metal halides.

It is further notable the conventional synthesis of a complex halidebased on the ammonium-halide route may not be applicable for forming thecomplex metal halide. Metal halides are used conventionally as startingmaterials. As some trivalent metal halides and tetravalent metalhalides, and in particular rare-earth halides, tend to form stable metalhalide hydrates, rendering it difficult to completely remove the watermolecules from those hydrates. Increasing the temperature can result inthe formation of undesired metal oxyhalide or metal oxyhydrate halidecompounds at a higher concentration. Further, metal halide hydrates andmetal oxyhalides, particularly those including rare earth metal, arerather stable compounds and less likely to form complex compound phasescontaining a high concentration of Li, such as Li₃RE(OX)Cl₃, wherein Xis a halogen other than Cl. Further, those complex compounds would notbe stable and would likely decompose into simple compounds.

The processes described in embodiments in this disclosure overcome theproblems noted above.

The process 100 may start at block 102. A reaction mixture may be formedincluding starting materials. In an embodiment, the starting materialscan include ammonium halide, NH₄X, wherein X includes Cl, Br, I, F, orany combination thereof. The starting material can further include oneor more metal compounds, wherein the metal can include an alkalielement, an alkaline earth element, a transition metal element, alanthanide, a rare earth element, or any combination thereof.

In particular embodiments, the metal compound may be non-hygroscopic. Inan aspect, the metal compound can include metal in the form of an oxide,carbonate, sulfate, hydrate, hydroxide, oxalate, acetate, nitrate, orany combination thereof. In particular aspects, the starting materialcan include more than one metal oxide. For example, the startingmaterials can include Me₂O_(k), wherein Me can be a divalent metal, atrivalent metal, a tetravalent metal, a pentavalent metal, or ahexavalent metal; k is the valence of the metal; and 2≤k≤6. Inparticular examples, Me can include a rare earth element including Ce,Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Pm, Sm, Sc, Tb, Tm, Yb, Sc, and Y,In, Zn, alkaline metal element, Hf, Zr, or any combination thereof. Inmore particular examples, the starting material can include one or moreof rare earth oxide or hydroxide or carbonate, ZrO₂ or Zr(OH)₄ orZr(CO₃)₂ or Zr(OH)₂CO₃.ZrO₂ or any combination thereof.

In another aspect, the starting material can include an alkali metalcompound, such as lithium carbonate, sodium carbonate, cesium carbonate,or a combination thereof. The starting material may further include anacid to facilitate the acidic synthesis in an aqueous, alcohol, or otherpolar molecular liquid solution.

In another particular instance, the metal compound may consist of alkalimetal compounds. For example, the starting material can include alkalimetal halides (e.g., NaCl, CsCl, and LiCl) and be free of a compoundincluding Me.

In implementations, the starting materials may be mixed at astoichiometric ratio. In other implementations, the ratio among thestarting materials can allow the formation of a non-stoichiometriccomplex metal halide.

In an exemplary implementation, a reaction mixture may be formedincluding NH₄X, one or more rare earth metal oxide (referred to as“RE₂O₃” hereinafter), lithium carbonate, and hydrochloric or hydrobromicacid. A reaction is illustrated below noting the starting materials andreaction products in the aqueous solution.

3^(*)Li₂CO₃ + RE₂O₃ + 12^(*)HX + 6^(*)NH₄X → 2^(*)(NH₄)₃REX₆ + 6^(*)LiX + 6^(*)H₂O + 3^(*)CO₂

The above reaction is an example intended to aid understanding of theprocess 100. In view of the application, a skilled artisan appreciatesanother alkali metal compound, such as Na₂CO₃ or NaCl, may be used as astarting material. Similarly, an oxide of a non-rare earth element, suchas Fe₂O₃, may be added to the reaction. A skilled artisan furtherappreciates the reaction products may change accordingly as the startingmaterials change.

In particular embodiments, the process 100 can include chemicallysubstituting moisture (i.e., water) in a hydrated salt containingMeX_(k) with NH₄X. In an aspect, the process can include forming(NH₄)_(n)Me^(k+)X_(n+k), wherein n>0; and 2≤k≤6. In a particularinstance, 0<n≤3. In particular instances, n can be 0.33, 0.5, 1, 1.5, 2,3, or 4, depending on what Me is. In the above-illustrated reaction,hydrated rare earth halide may be formed as an intermediate product andthe water in the hydrates may be replaced by NH₄X to form (NH₄)₃REX₆with an advantage non-forming hydrates compound, permitting to operateand keep hydroxide-free halide phases. As further illustrated, alkalimetal halide, such as LiX, is also formed.

In an instance, the mixture of the reaction products may be filtered toremove larger particles to facilitate the subsequent reaction in thesolid state. Larger particles can include impurities that come with anyof the starting materials, remaining particles of the startingmaterials, carbon, or any combination thereof.

The process 100 can continue to block 104. In an embodiment, the mixtureof the reaction products can be dried to facilitate a solid-statereaction of (NH₄)_(n)Me^(k+)X_(n+k) and alkali metal halide, MX, whereinM is an alkali metal element. Drying may be performed in air or dry airand/or under vacuum or reduced pressure, such as 100 mbar, 40 mbar, 1mbar, or even 0.01 mbar. In some instances, N₂ or Ar flow may be used tofacilitate removal of water. In another example, heat may be applied toaid evaporation of water. The heating temperature can be from 100° C. to160° C. Drying may be conducted until a trace amount of water is left inthe mixture, such as from 1 wt % to 3 wt %.

In an embodiment, the process 100 can include performing a solid-statereaction of (NH₄)_(n)Me^(k+)X_(n+k) and MX. In a particular example,from the above-illustrated reaction products, the solid-state reactionof (NH₄)₃REX₆ and LiX may be performed. In another embodiment, theprocess 100 can include forming (NH₄)_(n)M_(3−z)Me^(k+)X_(3+n+k−z),wherein −3≤z=<3. When z=0, (NH₄)_(n)M_(3−z)Me^(k+)X_(3+n+k−z) isstoichiometric. When z is not zero, (NH₄)_(n)M_(3−z) Me^(k+)X_(3+n+k−z)is non-stoichiometric. In particular instances, 0≤z<1. In a furtherinstance, the process 100 can include formingM_(3−z)(Me^(k+))_(f)X^(3−z+k*f), wherein −3≤z<3; 2≤k<6; 0≤f≤1.

The process 100 can continue to block 106. In an embodiment, forming theion conductive material can include decomposing ammonium halide. In anaspect, decomposition can include separate complex metal halide phasefrom ammonium halide phase. In another aspect, forming the ionconductive material can further include escaping of ammonium halide.

In an aspect, decomposition may be carried out in a crucible made of amaterial that is inert to the reactants and products. For example, thecrucible may be made of quartz, alumina, silica-alumina, BN, glassycarbon, or graphite. In particular implementations, graphite can have apyrolytic carbon coating.

In another aspect, decomposition may be conducted at a dry and neutralatmosphere, such as air or dry air. An inert gas, such as N₂ or Ar, maybe used to facilitate the process.

In a further aspect, decomposition may be performed for at least 15minutes to at most 24 hours. In an aspect, the solid-state solution maybe heated to a temperature in a range from 350° C. to 800° C. to allowpartial or full sublimation of ammonium halide. In some instances,sublimation of NH₄X can be monitored by weighing the escaped NH₄X thatis collected and condenses at the other side of the

In a further aspect, sublimation may be performed such that a majorityof ammonium halide, such as at least 60 wt %, at least 80 wt %, or atleast 90 wt % of ammonium halide may be removed compared to the weightof the initially added ammonium halide. In a further aspect, essentiallyof the aluminum halide may be removed by sublimation. In another aspect,sublimation may be performed such that residual ammonium halide may becontained by the ion conductive material.

In another aspect, decomposition of the ammonium-containing complexmetal halide can help remove reaction products other than the complexmetal halide from the solid-state solution. For instance, water, CO₂,ammonia, and halogen may be evaporated. Alternatively, the startingmaterials may be heated at a higher temperature so thatammonium-containing complex metal halide may be formed in one step. Anexemplary one-step reaction is illustrated below.

3^(*)Li₂CO₃ + RE₂O₃ + 18^(*)NH₄Br → 2^(*)(NH₄)₃Li₃REBr₉ + 6^(*)H₂O + 3^(*)CO₂ + 12^(*)NH₃.

Particularly, heating can be conducted such that the decomposition ofammonium and solid-state reaction may be carried out simultaneously. Forinstance, the heating temperature can be in a range from 250° C. to 650°C. or up to 800° C. to allow the formation of the solid-state solutionand sublimation of ammonium halide. It has been noted a relativelyhigher content of oxyhalide may be generated when using the one-stepsynthesis to form a complex metal halide.

In another embodiment, the process 100 can include forming the ionconductive material including the complex metal halide. In an aspect,the complex metal halide may be represented by M_(3−z)Me^(k+)X_(3−z+k).In another aspect, the complex metal halide may be represented byM_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein 0≤f≤1.

In an aspect, after decomposition, cooling may be performed. Forexample, cooling may be performed in air, dry air, or a nitrogenatmosphere. In another example, the cooling temperature may be below200° C., such as at most 100° C., at most 70° C., at most 50° C., or atmost 30° C. In particular implementations, cooling can be performed in adry atmosphere at room temperature (e.g., 20 to 25° C.). Optionally, Aror N₂ may be used to facilitate cooling.

In another aspect, the ion conductive material including the complexmetal halide may be formed after cooling.

In an embodiment, the complex metal halide may be formed including aparticular content of residual ammonium halide. In at least one example,the ion conductive material can include at least 2 ppm of ammoniumhalide for the total weight of the complex metal halide, such as atleast 10 ppm, at least 100 ppm, at least 300 ppm, at least 500 ppm, atleast 0.2 wt %, at least 0.5 wt %, or at least 1 wt % of ammonium halidefor the total weight of the complex metal halide. In another example,the ion conductive material can include at most 5 wt %, such as at most3 wt % of ammonium halide for the weight of the complex metal halide. Itis to be appreciated that the complex metal halide may include a contentof residual ammonium halide in a range including any of the minimum ormaximum values noted herein. In at least one example, the complex metalhalide may be essentially free of ammonium halide.

In an embodiment, the ion conductive material may be in the form ofpowder, such as including particles of complex metal halide. In anaspect, the powder can have an average particle size (D50) of at least0.1 microns, such as at least 0.3 microns, at least 0.5 microns, or atleast 1 micron. In another aspect, the average particle size may be atmost 1 mm, at most 800 microns, at most 500 microns, at most 200microns, at most 100 microns, at most 50 microns, at most 10 microns, atmost 5 microns, or at most 1 micron. In particular instances, the powdermay include particles having an average particle size in a rangeincluding any of the minimum or maximum values noted herein. In anotheraspect, the powder may include agglomerated particles.

In a further aspect, the particles can have a particular shape that canfacilitate improved formation and performance of an electrolyte and/orelectrode. For example, the particles can be spherical or elongated. Inanother example, the particles may have the shape of rods, flakes, orneedles. The shapes of the particles may be selected depending on 2D or1D anisotropy in the ion conductivity of the complex metal halide.

In another aspect, the powder can include particles having a particularaverage aspect ratio of length:width to facilitate the formation of anelectrolyte and/or an electrode having improved ion conductivity. In anexample, the average aspect ratio can be at least 1, such as at least1.2, at least 1.5, at least 2, at least 2.3, at least 2.5, at least 2.8,or at least 3. In another example, the average aspect ratio can be atmost 30, at most 25, at most 22, at most 20, at most 15, at most 12, atmost 10, at most 8, at most 5, or at most 4. Moreover, the particles canhave an average aspect ratio in a range including any of the minimum andmaximum values noted herein.

In an embodiment, the ion conductive material may include a certainimpurity at a relatively low content. The impurity can include simplemetal halides including Me^(k+)X_(k), such as a rare earth halide,alkali halides, such as LiCl and/or NaCl, metal nitrides, such as M₃N,and Me_(x)N_(y), or any combination thereof. Coefficients x and y arerespective valences of N and Me for an electric charge neutralMe_(x)N_(y). In further instances, the impurity can include amide (NH₂),imide (NH), hydroxide (OH), ammonia (NH₃), or any combination thereof.

In an embodiment, the complex metal halide can be represented byM_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein −3≤z≤3; 2≤k<6; and 0≤f≤1. Inparticular aspects, f is not zero. In particular aspects, z<3. In stillparticular instances, when f=0, z may not be 3. M can include an alkalimetal element; Me can include a divalent metal element, a trivalentmetal element, a tetravalent metal element, a pentavalent metal element,hexavalent metal element, or any combination thereof; and X can includea halogen.

In another embodiment, the complex metal halide may be represented byM_(3−z)Me^(k+)X_(3−z+k), wherein −3≤z≤3; M can include an alkali metalelement; Me can include a divalent metal element, a trivalent metalelement, a tetravalent metal element, a pentavalent metal element,hexavalent metal element, or any combination thereof; and X can includea halogen. In particular aspects, z<3.

In an aspect, M may consist of one or more alkali metal elementsincluding Li, Na, Cs, and Rb. In a further aspect, M can include Li. Forexample, M can consist of Li. In another aspect, M can include Li andanother alkali metal. For instance, M can include Li and at least one ofNa, Cs, and Rb. In another instance, M can consist of Li and at leastone of Na, Cs, and Rb. In more particular instances, M can consist of acombination of Li and Na. In another aspect, M can include Na, or acombination Na and at least one of Cs an Rb. In another instance, M canconsist of at least one of Na and Cs.

In particular implementations, Na can make up at most 40 mol % of M,such as at most 34 mol % of M. For example, M can include from 0 mol %to 40 mol % of Na. In particular examples, M can include up to 20 mol %of Na, or even more particularly, up to 10 mol % of Na. In at least oneinstance, Na can make up from 40 mol % to 100 mol % of M. In furtherparticular implementations, Li can make up at least 50 mol % or at least60 mol % or at least 66 mol % or at least 75 mol % of M. In a particularexample, M can include from 60 mol % to 100 mol % Li.

In another instance, Cs can make up at least 25 mol % of M, such as atleast 30 mol %, at least 40 mol %, or at least 50 mol % of M. In anotherinstance, Cs may make up at most 50 mol % or at most 40 mol % or at most30 mol % or at most 20 mol % or at most 10 mol % of M. In particularinstances, Cs may make up at most 1 mol % of M.

In an embodiment, the complex metal halide can be represented by(Li_(1−d),Na_(d))₂Li_(1−z)Me^(k+)X_(3+k−z), wherein 0<d<1; −0.95≤z≤0.95;Me can include a divalent metal element, a trivalent metal element, atetravalent metal element, a pentavalent metal element, hexavalent metalelement, or any combination thereof; and X can include a halogen.

In an embodiment, the complex metal halide represented by(Li_(1−d−e),Na_(d),M′_(e))₂Li_(1−z′)(Me^(k+))_(f)X_(3+k*f−z), wherein0≤d≤1; 0≤e<1; −3≤z′≤3; 2≤k<6; 0≤f≤1; M′ can include at least one of K,Rb, and Cs; and Me can include a divalent metal element, a trivalentmetal element, a tetravalent metal element, a pentavalent metal element,a hexavalent metal element, or any combination thereof; and X comprisesat least a halogen. In particular aspects, z′<3. In particular aspects,d+e>0. In particular aspects, f is not zero. In more particular aspects,e=0, and d is not zero.

In an aspect, d may be at least 0.01 or at least 0.05 or at least 0.1 orat least 0.2. In another aspect, d may be at most 0.8 or at most 0.5. Ina particular aspect, d can be in a range including any of the minimumand maximum values.

In an aspect, e may be at least 0.01 or at least 0.05 or at least 0.1 orat least 0.2. In another aspect, e may be at most 0.8 or at most 0.5. Ina particular aspect, e can be in a range including any of the minimumand maximum values.

In an embodiment, the complex metal halide represented byLi_(3−z)Me^(k+)X_(3−z+k), wherein −0.95≤z=<0.95; and Me can include adivalent metal element, a trivalent metal element, a tetravalent metalelement, a pentavalent metal element, hexavalent metal element, or anycombination thereof; and X can include a halogen.

In an aspect, z can be at most 0.5, such as at most 0.3 or at most 0.2.In another aspect, z may be at least −0.5 or at least −0.2. In aparticular example, z can be in a range including any of the minimum andmaximum values noted herein. When z is not 0, the complex metal halidecan be non-stoichiometric. When z is 0, the complex metal halide can bestoichiometric.

An exemplary divalent metal element can include an alkaline earthelement, such as Mg and/or Ca, Zn, or any combination thereof. Inparticular implementations, Me can include Zn, Ca, or any combinationthereof. In particular implementations, ions having relatively smallerradii, such as Zn and Mg, may be particularly suitable when the halogenincludes or consist of Cl; and ions having relatively larger radii, suchas Ca, may be particularly suitable when the halogen includes orconsists of Br. In another particular implementation, including asubstituting ion having a radius larger than the base ion may helpenlarge ion-conducting channels in the electrolyte material. Forexample, Me can include Ca and Y, wherein Ca can be suitable topartially substitute Y. In another implementation, a divalent elementhaving a relatively light weight, such as Mg, Zn, and Ca, may bepreferred. In certain instances, substituting Y with Sr or Ba may resultin the formation of compounds of SrX₂ or BaX₂, which may be an impurityimpacting bulk ionic conductivity of the complex metal halide.

An exemplary trivalent metal element can include a rare earth element, atrivalent metal other than a rare earth element, such as In, Ga, Al, orBi, or any combination thereof. In particular examples, Me can includeSc, Y, La, Gd, or any combination thereof. In more particular instances,Me can include Y, Gd, or a combination thereof.

An exemplary tetravalent metal element can include Zr, Hf, Ti, Sn, Ge,Th, or any combination thereof. In particular examples, Me can includeZr and Hf. In another particular example, Me can include Zr.

An exemplary pentavalent element can include Ta, Nb, W, Sb, or anycombination thereof.

In an aspect, Me can include a rare earth element, alkaline earth metalelement, 3d transition metal, Zn, Zr, Hf, Ti, Sn, Th, Ge Ta, Nb, Mo, W,Sb, In, Bi, Sc, Yb, Al, Ga, Fe or any combination thereof.

In a further aspect, Me can include a rare earth element, Zr, or anycombination thereof.

In another aspect, Me can include Y, Ce, Gd, Er, Zr, La, Yb, In, Mg, Zn,or any combination thereof.

In instances Me includes more than one metal element, k can be theaverage of the total of the valence of each Me metal element. Forexample, when Me includes a trivalent element and tetravalent element inequal molar quantity, k=(3+4)/2=3.5. In a particular aspect, k may be 3or 4 or 5.

In a further aspect, Me can include a rare earth element including Y,Gd, La, and/or Sc, an alkaline earth metal element, 3d transitionmetals, Zn, Zr, Hf, Ti, Sn, Th, Ta, Nb, Mo, W, Sb, In, Bi, Al, Ga, Ge orany combination thereof. In particular examples, Me can include Y, Gd,Zr, or any combination thereof. In particular instances, Me can includeY that is partially substituted by another Me element. For instance, Ymay be substituted by a particular content of another Me element thatcan facilitate improved crystalline structure and property of thecomplex metal halide. In a particular example, Me can include up to 70mol % of Y and from 5 mol % to 30 mol % of substitution Me element. In afurther example, Y may be partially substituted by an Me element havinga suitable effective ionic radius that may allow the formation of astable phase of the complex metal halide. In a particular example, theMe element may have an ionic radius that is smaller than the effectiveionic radius of La, 103.2 A and at least similar to the effective ionicradius of Li, 0.76 A. In more particular examples, the Me element mayhave an effective ionic radius from 0.76 A±5% to 93.5 A±5%.

In a particular implementation, Me can consist of Gd, Y, Ce, Er, Zr, Yb,or any combination thereof. For example, Me can consist of Y. In anotherexample, Me can consist of Y and at least one of Ce, Er, Zr, and Gd. Ina further example, Me consists of Yb and Ce. In another example, Me canconsist of two or more of In, Y, Zr, Hf, Sc, Zn, and Mg.

In an aspect, X can include at least one of Cl, Br, I, and F. Forexample, X can include Cl or Br. In another example, X can include F. Inanother example, X can include at least two of Cl, Br, and I. In stillanother example, X can include all of Cl, Br, and I.

In an aspect, X may include elements other than halogen. In someimplementations, X can include an anion group in addition to a halogen.Such anion group can include amide (—NH2), —(NH)_(0.5) (imide),hydroxide (—OH), —BF4, —BH₄ (borohydride), or a combination thereof. Theanion group may be included as an impurity or a dopant.

In particular aspects, X can consist of at least one of F, Cl, Br, andI, and optionally, an anion group including —NH₂ (amide), —(NH)_(0.5)(imide), —OH (hydroxide), —BH₄ (borohydride), —BF₄ groups, or anycombination thereof. For example, X can consist of one or both of Cl andBr and at least one anion group. In a further example, X may consist ofF and at least one anion group. In at least one embodiment, X may be oneor more halogen. In a particular example, M can be Li, Me can be acombination of In, Mg, Zr, and Sc, and X can be Cl or a combination ofCl and an anion group.

In another particular example, M can be Li, Me can be Y, Zr, and Hf, andX can be Cl or a combination of Cl and an anion group.

In another particular example, M can be Na, Me can be Zr, and X can beCl or a combination of Cl and an anion group.

In a particular embodiment, the complex metal halide is represented by(Li_((1−d−e)),Na_((d)),M′_((e)))₂Li_((1−z))Me³⁺ _((1−u−p−q−r))Me⁴⁺_((u))Me²⁺ _((p))Me⁵⁺ _((q))Me⁶⁺_((r))(Cl_((1−y−w))Br_((y))I_((w)))_((6+u−p+2q+3r−Z)), wherein 0≤d≤1;0≤e<1; −3≤z≤3; M′ includes at least one of K, Rb, Cs; M³⁺ includes arare-earth element, In, Bi, Sc, Y, Al, Ga or any combination thereof;Me⁴⁺ is Zr⁴⁺, Hf⁴⁺, Ti⁴⁺, Sn⁴⁺, Th⁴⁺, Ge⁴⁺ or any combination thereof;Me²⁺ is Mg²⁺, Zn²⁺, Ca²⁺, Yb²⁺, Eu²⁺ or any combination thereof; Me⁵⁺ isTa⁵⁺, Nb⁵⁺, W⁵⁺, Sb⁵⁺, or any combination thereof; Me⁶⁺ is W⁶⁺, Mo⁶⁺, orany combination thereof; 0<=w<=1; 0<=y<=1; −0.95<z<0.95; 0<=u<0.95;0<=p<0.95; 0<=q<0.95; and 0<=r<0.95.

In particular aspects, M³⁺ can include Y³⁺, Gd³⁺, In³⁺, Er³⁺, Sc³⁺, orany combination thereof. In more particular aspects, M³⁺ can consist ofY³⁺, Gd³⁺, In³⁺, Er³⁺, Sc³⁺, or any combination thereof.

In particular aspects, M⁴⁺ can include Zr⁴⁺, Hf+, Ce⁴⁺, or a combinationthereof. In more particular aspects, M⁴⁺ can consist of Zr⁴⁺, Hf⁴⁺,Ce⁴⁺, or a combination thereof.

In another particular aspect, any one or more of p, q, r, and u can be0. In more particular aspects, all of p, q, r, and u can be 0.

In a particular aspect, k can be 2 or 3 or 4 or 5.

In another particular aspect, the complex metal halide is represented by(Li_((1−d)),Na_((d)))₂Li_((1−z))RE_((1−u))Zr⁴⁺_((u))(Cl_((1−y))Br_((y)))_((6+u−z)), wherein 0<d<1; 0<z<0.95; and0<=u<0.95. In an instance, d may be at least 0.0001, at least 0.001, atleast 0.005, at least 0.008, at least 0.01, at least 0.02, at least0.03, at least 0.05, or at least 0.06. In a further instance, d may beat most 0.5, at most 0.3, at most 0.2, at most 0.1, at most 0.08, atmost 0.06, at most 0.05, at most 0.04, or at most 0.03. In a furtherinstance, d may be in a range including any of the minimum and maximumvalues noted herein. For example, 0<d<0.05. In a further instance, z canbe at least 0.02, at least 0.03, at least 0.05, at least 0.07, at least0.09, at least 0.1, at least 0.15, at least 0.18, or at least 0.2. Inanother instance, z can be at most 0.5, at most 0.4, at most 0.38, atmost 0.35, at most 0.33, at most 0.3, at most 0.28, at most 0.25, atmost 0.23, or at most 0.2. Moreover, z can be in a range including anyof the minimum and maximum values noted herein. For instance, 0<z<0.2.In another instance, u may be at least 0.01, at least 0.03, at least0.05, at least 0.07, at least 0.09, at least 0.1, at least 0.13, atleast 0.15, at least 0.18, at least 0.2, at least 0.22, at least 0.25 orat least 0.3. In another instance, u may be at most 0.8, at most 0.78,at most 0.75, at most 0.73, at most 0.7, at most 0.68, at most 0.65, atmost 0.63, or at most 0.6. Moreover, u can be in a range including anyof the minimum and maximum values noted herein. For instance, 0.2<u<0.6.

In a particular embodiment, the complex metal halide may be doped with adopant. In particular examples, Li may be partially substituted by adopant. In more particular examples, the dopant can include ammonium,such as ammonium halide NH₄X, wherein X can be Cl, Br, I, F, or anycombination thereof.

In an aspect, the complex metal halide can include ammonium halide of atmost 20 wt % for the total weight of the complex metal halide, such asat most 15 wt %, at most 10 wt %, at most 8 wt %, at most 5 wt %, or atmost 3 wt % of ammonium halide for the total weight of the complex metalhalide. In another aspect, ammonium halide may be present in the ionconductive material in a content of at least 10 ppm by mass of ammoniumhalide for the total weight of the complex metal halide, such as atleast 100 ppm, at least 500 ppm, at least 0.1 wt %, at least 0.3 wt %,at least 0.5 wt %, at least 0.8 wt %, or at least 1 wt % of ammoniumhalide for the total weight of the complex metal halide. Moreover, thecomplex metal halide can include ammonium halide in a content in a rangeincluding any of the minimum and maximum values noted herein.

Referring to FIG. 2, an exemplary process 200 for forming a solid ionconductive material is illustrated. The process 200 can include stepssimilar to steps illustrated in blocks 102, 104, and 106 of FIG. 1 anddescribed in embodiments with respect to the process 100. The process200 can continue to block 208 after obtaining the complex metal halideat block 106. In an embodiment, the process 200 can include forming asolid ion conductive material including a single crystal materialincluding the complex metal halide. In an aspect, crystal growth may becarried out in a crucible made of a material that is inert to thecomplex metal halide. For example, the crucible may be made of quartz,alumina, silica-alumina, BN, glassy carbon, or graphite. In particularimplementations, graphite can have a pyrolytic carbon coating.

The complex metal halide obtained by the process 100 can be directlyused as a charge to form a single crystal. In an aspect, the process 200can include partially or fully melting complex metal halide. In someinstances, a dopant material, such as a metal compound, may be added tothe melt to facilitate substitutions of one or more metal elements ofthe complex metal halide.

In a further aspect, the process 200 can include a particular crystalgrowth rate that can facilitate the growth of single crystals having amacroscopic size, such as a monocrystalline block of up to 10centimeters. For example, the growth rate can be at least 0.2 mm/hour,at least 0.3 mm/hour, or at least 0.5 mm/hour. In another instance, thegrowth rate can be at most 10 mm/hour, such as at most 8 mm/hour, atmost 6 mm/hour, at most 5 mm/hour, at most 3 mm/hour, or at most 1mm/hour. In a particular instance, the growth rate can be in a rangeincluding any of the minimum and maximum values noted herein.

In another aspect, the process 200 can include cooling the melt. Inparticular aspects, cooling can be conducted in a controlled manner tosupport the formation of a single crystal having the complex metalhalide. In particular instances, cooling can be facilitated by anexternal thermal field with a cooling rate of 10° C./hour to 50°C./hour. In another particular instance, the starting material of thecomplex metal halide may form an incongruent melting phase due to thepresence of an impurity, such as a simple metal halide, and in thoseinstances, the melt can include a mixture of off-stoichiometry includingthe complex metal halide and a dopant material in an excessive amount tofacilitate the formation of stoichiometric single-phase crystals atself-flux conditions.

The single crystal can have the same composition as the complex metalhalide formed by the process 100 and described in the embodimentsherein.

The single crystals can be smaller chunks of the order of a fewmillimeters or a densified block or large ingots up to tens ofcentimeters in size.

In an embodiment, the ingots or blocks may be ground to remove visibleimpurity and/or parasitic phases when they are present.

In a further embodiment, the single crystal may be ground to form finepowder having single crystal particles. In an exemplary application,single crystal particles may be used to form an ion conductive componentin an electrochemical device. In another embodiment, the single crystalingot or block may be sliced into thin sheets. For instance, the thinsheet can have a thickness from 5 microns to 500 microns.

In a particular embodiment, the process 200 can include forming a singlecrystal having a particular crystallographic orientation. In an aspect,oriented growth of the single crystal can be performed. In particularaspects, oriented crystal growth can be conducted for crystals that areanisotropic. In an exemplary implementation, crystallization of pelletsor particles elongated in the crystallographic direction with higherconductivity can be conducted. In another example, a high-temperaturegradient, such as 10° C./cm or higher, may be applied to facilitate theoriented growth of a single crystal. In a further example, an X-raygoniometer can be used to identify the orientation of the crystal. Inanother aspect, oriented crystal growth may be conducted using a strongpermanent magnetic field, solidification under a strong electric field,or any combination thereof, for crystals that are anisotropy formagnetic permeability or dielectric constant. In still another aspect,utilizing a supporting seeding layer having a lattice parameter close tothe oriented ceramics material and solidification in the flux media mayhelp keep the oriented polycrystalline structure.

In another aspect, a single crystal can be sliced such that thecrystallographic direction with a higher conductivity may be in thethickness direction of the thin sheet.

In a particular embodiment, the ion conductive material can include anoriented crystalline material, such as a monocrystalline material havinga crystallographic orientation represented by <HKL> or <HKLM>, whereinan ionic conductivity in the crystallographic orientation of <HKL> or<HKLM> is higher than an ionic conductivity in a differentcrystallographic orientation that the single crystal may be oriented.

For example, Li₃YBr₆ has a higher ion conductivity in thecrystallographic orientation <100> compared to <001>. A Li₃YBr₆ singlecrystal having the crystallographic orientation of <100> may be formedto have higher bulk ion conductivity. Alternatively, a slice of Li₃YBr₆having a cut surface extending in crystallographic orientation of <001>may be formed from a single crystal, and the thickness of the sliceextends in the crystallographic orientation of <100>.

Referring to FIG. 3A, a sheet 300 is illustrated. In an embodiment, thesheet 300 can include the single crystal described in embodimentsherein. The sheet 300 can have a thickness t extending between the majorsurfaces 302 and 304. FIG. 3B includes an exemplary illustration of thecrystallographic orientations of the single crystal. The single crystalcan have a mika-like layered structure, wherein the length of the layersextends in the crystallographic direction <100> and the stack of layersextends in the crystallographic direction <001>. The particular singlecrystal can have greater ion conductivity in the crystallographicdirection <100> compared to <001>. In particular instances, thethickness t of the sheet 300 can extend in the direction ofcrystallographic direction <100>. In further instances, one or both ofthe major surfaces of 302 and 304 can be a sliced surface.Alternatively, the sheet 300 can be formed by oriented crystal growth tohave the crystallographic orientation, wherein the thickness t extendsin the crystallographic direction <100>.

It is notable the forming processes of embodiments herein can allow theformation of the ion conductive material having higher purity. It isfurther notable the ion conductive material with a higher purity canhave further improved ion conductivity.

Using a conventional method, such as ball-milling-based solid-statereaction, to form a complex metal halide can result in higher contentsof impurities, such as simple metal halide. When using complex metalhalide having higher contents of simple metal halide contamination ordirectly using simple compounds as the starting material to growcrystals following the process of Bridgman-Stockbarger, Gradient-Freeze,Czochralski, or Bagdasarov (Horizontal Bridgman), the melt displaysincongruent melting and formation of higher contents of impurity andparasitic phases in resulted crystals. The impurity and parasitic phasesinclude one or more simple metal halide, such as LiX and Me^(k+)X_(k),wherein X is a halogen, such as Cl and/or Br.

The processes of embodiments herein can allow the formation of complexmetal halide with low content of impurity. In an embodiment, the complexmetal halide can have a total content of simple metal halide of at most15 wt % for the total weight of the complex metal halide, such as atmost 12 wt %, at most 11 wt %, at most 10 wt %, at most 9 wt %, at most8 wt %, at most 7 wt %, at most 6 wt %, at most 5 wt %, at most 4 wt %,at most 3 wt %, at most 2 wt %, at most 1 wt %, or at most 0.5 wt % forthe total weight of the complex metal halide. In particular embodiments,the single crystal of complex metal halide can be essentially free ofsimple metal halides. For instance, the total content of all simplemetal halides may be less than 0.2 wt % for the weight of the singlecrystal. It is also notable that the complex metal halide of embodimentsherein has higher bulk ion conductivity compared to that made usingconventional methods.

In an embodiment, performing crystal growth can facilitate furtherpurification of the complex metal halide. In further instances, crystalgrowth can facilitate the formation of the ion conductive material withimproved bulk ion conductivity. It is notable a single crystal of thecomplex metal halide of embodiments herein tends to have furtherimproved bulk ion conductivity compared to non-single crystal form(e.g., powder) having the same complex metal halide of embodimentsherein.

In at least one embodiment, a single crystal of embodiments herein mayinclude a low content of impurity of nitride-based phase. Nitride-basedphase can include one or more phases of metal nitride, metal oxynitride,metal carbon nitride, or any combination thereof. The formation ofnitride-based phase may result from the process 100, the process 200, ora combination thereof. In some instances, the presence of a particularspecies of metal nitride, such as Li₃N may help improve bulk ionconductivity of the metal halide material. Referring to FIG. 4, aprocess 400 for forming an ion conductive material is illustrated. Theprocess 400 can include all the steps illustrated in FIG. 1 anddescribed in embodiments with respect to the process 100.

In an embodiment, the process 400 can include forming a solid conductivematerial including an oriented ceramic material. In an aspect, theparticles of complex metal halide formed by the process 100 may be used.In an instance, the particles can have a particular shape, such as anelongated shape, and may be arranged such that the longitudinal axis ofthe particles extends in parallel in the direction of thecrystallographic orientation with higher ion conductivity. In anotherinstance, casting, compacting, pressing, heating, molding, or anycombination thereof, may be used to facilitate orienting the particles.In another instance, a magnetic field, electric discharge, thermalgradient, or a combination thereof may be used to facilitate the crystalorientation of the ceramic particles.

In another embodiment, the process 400 can include performing crystalgrowth to form an oriented ceramic. In an aspect, the process 400 caninclude forming a melt similar to process 200. In a further aspect,crystal growth can be conducted at a particular growth rate. Forexample, the growth rate may be at least 8 mm/hour, at least 10 mm/hour,at least 15 mm/hour, or at least 20 mm/hour. In another instance, thegrowth rate can be at most 80 mm/hour, at most 70 mm/hour, at most 60mm/hour, at most 50 mm/hour, or at most 40 mm/hour. IN another instance,the growth rate can be in a range including any of the minimum andmaximum values noted herein. In another aspect, a thermal gradient canbe applied to facilitate the growth of an oriented polycrystallinecrystal.

In an embodiment, the process 400 can include forming a single crystalas described in embodiments related to the process 200. In an aspect,single crystal pellets may be arranged to form a ceramic ion conductivematerial having a particular crystallographic orientation. In anexample, casting, compacting, pressing, heating, molding, or anycombination thereof, may be used to facilitate the formation ofcrystal-orientated ceramic ion conductive material. In a particularinstance, the single crystal pellets can be oriented and having thepreferred crystallographic orientation.

In an example, a complex metal halide can be anisotropic having higherion conductivity in the crystallographic orientation <100> and ionconductivity in the crystallographic orientation lower <001>. Referringto FIG. 3b , single crystal or ceramic pellets of the complex metalhalide 322 can be arranged as illustrated to form a crystal-orientedceramic material.

The solid ion conductive material of embodiments herein can be indifferent forms. In an embodiment, the ion conductive material caninclude powder including the complex metal halide. In anotherembodiment, the ion conductive material can include a single crystal ofthe complex metal halide. For instance, the ion conductive material caninclude a powder including single crystal particles. In anotherinstance, the ion conductive material can include a monocrystallinesheet, a monocrystalline film, a monocrystalline block, amonocrystalline ingot, or a single crystal in another form, or anycombination thereof. In a further embodiment, the ion conductivematerial can include a ceramic material including the complex metalhalide. For instance, the ceramic material may include ceramicparticles, single crystal particles, or any combination thereof.

In another embodiment, the solid ion conductive material can bepolycrystalline, monocrystalline, or a crystallographic orientedcrystalline material. For instance, the solid conductive material can bea single crystal of complex metal halide. In another instance, the solidconductive material can be a ceramic consisting of single crystals ofcomplex metal halide. In another instance, the solid conductive materialcan be a crystallographic oriented crystalline material of the complexmetal halide.

In an embodiment, the solid ion conductive material may include acontent of impurity. Impurity may be present as a different phase thanthe complex metal halide or complexed with metal halide in the samephase. For instance, a simple metal halide may be present in a separatephase than the complex metal halide. In instances, ammonium halide maybe fully or partially complexed with the complex metal halide. Inparticular, the solid ion conductive material can include improvedpurity compared to a conventional solid ion conductive material that maybe represented by the same general formula but is formed using a processdifferent than the processes noted in embodiments herein. For instance,the total of the contents of all the impurities (also referred to as“the total content of impurity”) may make up at most 15 wt % for theweight of the complex metal halide in the solid ion conductive materialof embodiments herein. For example, the total content of impurity can beat most 14 wt % for the weight of the complex metal halide, such as atmost 13 wt %, at most 12 wt %, at most 11 wt %, at most 10 wt %, at most9 wt %, at most 8 wt %, at most 7 wt %, at most 6 wt %, at most 5 wt %,at most 4 wt %, at most 3 wt %, at most 2 wt %, at most 1 wt %, at most0.5 wt %, at most 0.3 wt %, at most 0.1 wt %, at most 500 ppm, at most300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30ppm, at most 20 ppm, or at most 10 ppm for the weight of the complexmetal halide. In another instance, the complex metal halide can includea total content of impurity of at least 0.2 ppm for the weight of thecomplex metal halide, such as at least 0.5 ppm, at least 1 ppm, or atleast 2 ppm for the weight of the complex metal halide. In anotheraspect, the total content of impurity may be in a range including any ofthe minimum or maximum values noted herein.

Content of impurity phase can be determined as follows. The phase foreach impurity can be detected by XRD analysis coupled with Rietveldrefinements for quantitative analysis through the presence ofcharacteristic diffraction peaks corresponding to the parasitic phases.Rietveld Refinements (RR) can analyze the shape and position of thepeaks at an XRD diagram to identify quantitatively the contribution ofthe various phases by collecting the 2θ data at XRD diffraction with asmall incrementation of 2θ angle and converting the XRD data into aratio of different phases.

For nitride-based impurity phase, LECO analysis may also be used todetermine the presence and quantify the phase, particularly when thenitride-based impurity phase is present at below 0.1% at the molar ormass quantity. LECO analysis is based on combustion of the sample andanalyzing the presence of nitrogen (or also sulfur, carbon, hydrogen,oxygen) through boiled material gas thermal conductivity or Infra-Redabsorption diagrams.

In a further aspect, the content of all nitride-based impurity phase,such as metal nitride, metal oxynitride, and/or metal-carbon nitride,present in the ion conductive material can be at most 0.5 wt % for theweight of the complex metal halide, such as at most 0.3 wt %, at most0.2 wt %, at most 0.1 wt %, at most 500 ppm, at most 300 ppm, at most100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm,or at most 10 ppm for the weight of the complex metal halide. In anotherinstance, the content of all metal nitride can be at least 0.2 ppm forthe weight of the complex metal halide, such as at least 0.5 ppm, atleast 1 ppm, or at least 2 ppm for the weight of the complex metalhalide. In another aspect, the content of all nitride-based phases maybe in a range including any of the minimum or maximum values notedherein.

In a further aspect, the content of alkali halide (MX) can be at most 10wt % for the weight of the complex metal halide, such as at most 9 wt %,at most 8 wt %, at most 7 wt %, at most 6 wt %, at most 5 wt %, at most4 wt %, at most 3 wt %, at most 2 wt %, at most 1 wt %, at most 0.5 wt%, at most 0.3 wt %, at most 0.2 wt %, at most 0.1 wt %, at most 500ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm,at most 30 ppm, at most 20 ppm, or at most 10 ppm for the weight of thecomplex metal halide. In another instance, the content of MX can be atleast 0.2 ppm for the weight of the complex metal halide, such as atleast 0.5 ppm, at least 1 ppm, or at least 2 ppm for the weight of thecomplex metal halide. In another aspect, the content of MX may be in arange including any of the minimum or maximum values noted herein.

In a further aspect, the content of metal oxyhalide (MeOX), such as rareearth oxyhalide, can be at most 5 wt % for the weight of the complexmetal halide, such as at most 4 wt %, at most 3 wt %, at most 2 wt %, atmost 1 wt %, at most 0.5 wt %, at most 0.3 wt %, at most 0.2 wt %, atmost 0.1 wt %, at most 500 ppm, at most 300 ppm, at most 100 ppm, atmost 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most10 ppm for the weight of the complex metal halide. In another instance,the content of MeOX phase can be at least 0.2 ppm for the weight of thecomplex metal halide, such as at least 0.5 ppm, at least 1 ppm, or atleast 2 ppm for the weight of the complex metal halide. In anotheraspect, the content of MeOX phase may be in a range including any of theminimum or maximum values noted herein. In particular aspects, thecomplex metal halide can be essentially free of MeOX.

In a further aspect, the content of metal nitride Me_(x)N_(k) can be atmost 0.3 wt % for the weight of the complex metal halide, such as atmost 0.1 wt %, at most 500 ppm, at most 300 ppm, at most 100 ppm, atmost 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most10 ppm for the weight of the complex metal halide. In another instance,the content of metal nitride can be at least 0.2 ppm for the weight ofthe complex metal halide, such as at least 0.5 ppm, at least 1 ppm, orat least 2 ppm for the weight of the complex metal halide. In anotheraspect, the total content of metal nitride Me_(x)N_(k) may be in a rangeincluding any of the minimum or maximum values noted herein.

In a further aspect, the content of metal nitride M_(x)N can be at most0.3 wt % for the weight of the complex metal halide, such as at most 0.1wt %, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm,at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm forthe weight of the complex metal halide. In another instance, the contentof metal nitride can be at least 0.2 ppm for the weight of the complexmetal halide, such as at least 0.5 ppm, at least 1 ppm, or at least 2ppm for the weight of the complex metal halide. In another aspect, thetotal content of metal nitride MeN may be in a range including any ofthe minimum or maximum values noted herein.

In this disclosure, the total content of nitride-based phase and thecontent of metal nitrides, such as alkali nitride and Me_(x)N_(k), canbe detected using the following methods. The ion conductive material canbe dissolved in the water, as complex metal halide can be hygroscopic.Metal nitride is not hygroscopic and can be collected and analyzed afterfiltering the aquatic solution. X-ray diffraction analysis can be usedto detect metal nitride at the content of above 0.2 wt %. For thecontent lower than 0.2 wt %, LECO can be used.

For the content of simply metal halide, X-ray diffraction can be used toanalyze the ion conductive material without dissolving the ionconductive material.

In particular instances, the solid ion conductive material can includeNH₃, NH₄X, or a combination thereof, wherein X includes a halogen. In anexample, NH₃ and/or NH₄X may be present as a separate phase in additionto the complex metal halide. In another example, NH₃ and/or NH_(4X) maybe a dopant or an impurity of the complex metal halide.

In still another instance, the solid ion conductive material can includeLi₄(NH₂)₃Cl, Li₇(NH₂)₆Cl, Li₂Br(NH₂), Li₁₃[NH]₆Cl, LiCl.NH₃, LiBr.4NH₃,or a combination thereof. In an instance, one or more of the compoundsmay be present in separate phases in addition to the complex metalhalide. In another example, one or more of the compounds may be aby-product resulted from the process 100, 200, and/or 300. In anotherexample, the compounds may be a dopant or an impurity present of thecomplex metal halide.

In an embodiment, the ion conductive material can have a bulk ionconductivity, measured by electrochemical impedance spectroscopyperformed on pelletized samples sandwiched between ion-blockingelectrodes, of at least 0.01 mS/cm, such as at least 0.05 mS/cm, atleast 0.08 mS/cm, or at least 0.1 mS/cm, or at least 0.3 mS/cm, or atleast 0.5 mS/cm. In particular examples, the bulk ion conductivity canbe at least 0.6 mS/cm, at least 1.2 mS/cm, at least 1.8 mS/cm, or atleast 2.2 mS/cm. In another example, the bulk ion conductivity can be atmost 15 mS/cm, at most 13 mS/cm, at most 11 mS/cm, at most 8 mS/cm, atmost 7.2 mS/cm, or at most 6.2 mS/cm at. In a particular example, thebulk ion conductivity can be in a range including any of the minimum andmaximum values noted herein. The bulk ion conductivity may be measuredat room temperature, such as 22° C., and at activation energy in therange of 0.2 eV and 0.5 eV. In further instances, the activation energyfrom 0 to 1 eV may be used for the temperature from 200° C. to −80° C.For the temperature from 80° C. to −30° C., the activation energy may befrom 0.1 to 0.6 eV. For above 0° C. or below 10° C., the activationenergy can be from 0.1 to 0.5 eV.

In an embodiment, a solid-state electrolyte can include the ionconductive material. The ion conductive material can be single crystal,polycrystalline, or a combination thereof. The solid-state electrolytecan have improved ion conductivity compared to solid-state electrolyteincluding conventionally formed complex lithium-based metal halide. In aparticular example, the solid-state electrolyte can consist of the ionconductive material. In more particular examples, the solid-stateelectrolyte can consist of the single crystal complex metal halide,polycrystalline complex metal halide, or oriented crystalline complexmetal halide including single crystal having a particularcrystallographic orientation or oriented ceramics. In particularapplications, an electrolyte may include the crystallographic orientedsolid ionic conductive material, wherein the electrolyte may have athickness extending in the direction that is parallel to the orientationof the solid ionic conductive material.

In an embodiment, a composite ion conductive layer can include the ionconductive material and an organic material. The organic material caninclude as a binder material, a polymeric electrolyte material, or acombination thereof. In another example, the composite ion conductivelayer may include a plasticizer, a solvent, or a combination thereof. Anexemplary organic material can include polytetrafluoroethylene (PTFE),polyvinylidene fluoride (PVdF), fluorine rubber, polypropylene, anethylene-propylene-diene monomer (EPDM), sulfonated EPDM, natural butylrubber (NBR), paraffin wax, polypropylene carbonate, polyisobutylene,polyvinyl pyrrolidone, polymethyl methacrylate, poly(propylene oxide),polyvinyl chloride, poly(vinylidene fluoride), poly(acrylonitrile),poly(dimethylsiloxane), poly[bis(methoxy ethoxyethoxide)-phosphazene],polyethylene carbonate, polypropylene glycol, polycaprolactone,poly(trimethylene carbonate), hydrogenated nitrile butadiene rubber,poly(ethylene vinyl acetate), high density polyethylene, low densitypolyethylene, polyurethane, or any combination thereof. In anotherexample, the composite ion conductive layer can include a lithium salt.An exemplary lithium salt can include LiSbF₆, LiN(SO₂CF₃)₂,LiN(SO₂C₂F₅)₂, LiN(SO₂CF₃)(SO₂C₄F₉), LiC(SO₂CF₃)₃, LiAsF₆, LiClO₄,LiPF₆, LiBF₄, LiCF₃SO₃, or any combination thereof.

In another embodiment, a mixed electron and ion conductive layer caninclude the ion conductive material. In an aspect, the mixed electronand ion conductive layer can further include a cathode active material.An example of the cathode active material can include, but not limitedto, lithium-containing transition metal oxides, such as Li(NiCoAl)O₂ andLiCoO₂, transition metal fluorides, polyanions, and fluorinatedpolyanion materials, and transition metal sulfides, transitions metaloxyfluorides, transition metal oxysulfides, transition metaloxynitrides, or the like, or any combination thereof.

In another aspect, the mixed ion and electron conductive layer caninclude an anode active material. An exemplary anode active material caninclude carbon materials, such as artificial graphite, graphite carbonfibers, resin baking carbon, pyrolytic vapor-grown carbon, coke,mesocarbon microbeads (MCMB), furfuryl alcohol resin-baked carbon,polyacene, pitch-based carbon fibers, vapor-grown carbon fibers, naturalgraphite, non-graphitizable carbon, or the like, metal materialsincluding lithium metal, lithium alloy, or the like, oxides, nitrides,tin compounds, silicon compounds, or any combination thereof.

In some instances, the mixed ion and electron conductive layer caninclude an electron conductive additive. An example of the electronconductive additive can include carbon fiber, carbon powder, stainlesssteel fiber, nickel-coated graphite, or the like, or any combinationthereof.

In an embodiment, a solid-state lithium battery can include anelectrolyte disposed between an anode and a cathode. Referring to FIG.5, a portion of a cross-section of an exemplary solid-state battery 500is illustrated. The electrolyte layer 502 can be any of the electrolyteor composite layers noted in embodiments herein. The anode 504 overliesthe electrolyte 502. In an embodiment, the anode 504 can include thesolid ion conductive material and an anode active material. Inparticular instances, the anode 504 may be a 3 dimensionally structuredanode. In another embodiment, the anode 504 may be a metal anode. Forinstance, the anode may consist of lithium. The cathode 506 may bedisposed on the other side of the electrolyte 506 opposite the anode502. The cathode 506 can include the solid electrolyte material and anactive cathode material. In a particular embodiment, the cathode 506 maybe a 3 dimensionally structured cathode.

In a particular example, the electrolyte 502 can be the single crystalsheet 302 illustrated in FIG. 3. The anode 504 can be overlying themajor surface 304 illustrated in FIG. 3. The major surface 306 isillustrated in FIG. 3 can be over the cathode 506.

Known techniques can be used to form an electrolyte, a composite ionconductive layer, an anode, a cathode, or another component of asolid-state lithium battery with the solid electrolyte material. Suchtechniques include, but are not limited to, casting, molding,deposition, printing, pressing, heating, or the like, or any combinationthereof. In particular implementations, for forming a multi-layerstructure, the layers, such as electrolyte and anode and/or cathode maybe formed separately and then laminated to form a multi-layer structure.Alternatively, a stack of green electrolyte and anode and/or cathodelayers may be formed followed by a further treatment, such as pressing,heating, drying, or any combination thereof to form the finally formedmulti-layer structure.

In particular embodiments, the single-crystal block or ingot can beprocessed together with cathode or anode active materials, for example,by mechanical pressing or by thermally-activated co-extrusion, to ensureintimate electrode to electrolyte contact.

In another particular embodiment, the single crystal block and ingot maybe grown directly around the particles of the anode and/or cathodeactive materials to form a mixed electron and ion conductive layer. Inan aspect, a mixed ion and electron conductive layer can include thesingle-crystal ion conductive material including inclusions including ananode or cathode active material. In another aspect, a mixed ion andelectron conductive layer can include an anode or cathode activematerial that is densely packed within a single crystal ingot or block.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described herein. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the embodiments as listed below.

EMBODIMENTS

Embodiment 1. A solid ion conductive material, comprising a complexmetal halide, wherein:

-   -   the complex metal halide is doped with a dopant including        ammonium; and    -   the complex metal halide is represented by        M_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein:    -   −3≤z<3;    -   2≤k<6;    -   0≤f≤1;    -   M comprises an alkali metal element;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, a hexavalent metal element, or any combination thereof;        and    -   X comprises a halogen.

Embodiment 2. A solid ion conductive material, comprising:

-   -   a complex metal halide represented by        M_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein:    -   −3≤z<3;    -   2≤k<6;    -   0≤f≤1;    -   M comprises an alkali metal element;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, a hexavalent metal element, or any combination thereof;        and X comprises a halogen; and    -   at least one of the electric charge neutral Me_(x)N_(k) or        M_(x)N, wherein x is a valence of N and k is the valence of Me.

Embodiment 3. The solid ion conductive material of embodiment 1 or 2,wherein the complex metal halide is represented by(Li_(1−d−e),Na_(d),M′_(e))₂Li_(1−z′)(Me^(k+))_(f)X_(3+k*f−z), wherein:

-   -   0≤d≤1;    -   0≤e<1;    -   M consists of at least one of Li, Na, and M′; and    -   M′ consists of at least one of K, Rb, and Cs.

Embodiment 4. A solid ion conductive material, comprising a complexmetal halide represented by(Li_(1−d−e),Na_(d),M′_(e))₂Li_(1−z)(Me^(k+))_(f)X_(3+k*f−z), wherein:

-   -   −3≤z<3;    -   2≤k<6;    -   0≤f≤1;    -   0<d≤1;    -   0≤e<1;    -   M comprises an alkali metal element;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, a hexavalent metal element, or any combination thereof;        and X comprises a halogen; and    -   at least one of electric charge neutral Me_(x)N_(k) or M_(x)N,        wherein x is a valence of N and k is the valence of Me;    -   M consists of at least one of Li, Na, and M′; wherein M′        consists at least one of K, Rb, and Cs.

Embodiment 5. The solid ion conductive material of any one ofembodiments 1 to 4, wherein z is between −0.95 and 0.95 and M consistsof Na and Li.

Embodiment 6. The solid ion conductive material of any one ofembodiments 1 to 5, wherein Me comprises one or more of a rare earthelement, alkaline earth metal element, 3d transition metal, Zn, Zr, Hf,Ti, Sn, Th, Ge, Ta, Nb, Mo, W, Sb, In, Bi, Al, Ga, Fe or any combinationthereof.

Embodiment 7. The solid ion conductive material of any one ofembodiments 1 to 6, wherein Me comprises a rare earth element, Zr, orany combination thereof.

Embodiment 8. The solid ion conductive material of any one ofembodiments 1 to 7, wherein Me comprises Y, Ce, Gd, Er, Zr, La, Yb, In,Mg, Zn, or any combination thereof.

Embodiment 9. The solid ion conductive material of any one ofembodiments 1 to 8, wherein X consists of at least one of F, Cl, Br, andI, and optionally, an anion group including —NH₂ (amide), —(NH)_(0.5)(imide), —OH (hydroxide), —BH₄ (borohydride), —BF₄ groups, or anycombination thereof.

Embodiment 10. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of Gd, Y, or a combinationthereof.

Embodiment 11. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of Ce, Y, or a combinationthereof.

Embodiment 12. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of Er, Y, or a combinationthereof.

Embodiment 13. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of Yb, Ce, or a combinationthereof.

Embodiment 14. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of Y, Zr, or a combinationthereof.

Embodiment 15. The solid ion conductive material of any one ofembodiments 1 to 9, wherein Me consists of two or more of In, Y, Zr, Hf,Sc, Zn, and Mg.

Embodiment 16. The solid ion conductive material of any one ofembodiments 1 to 15, wherein the halogen consists of one of Cl, Br, I,and F.

Embodiment 17. The solid ion conductive material of any one ofembodiments 1 to 16, wherein the halogen consists of at least two ormore of Cl, Br, I, and F.

Embodiment 18. The solid ion conductive material of any one ofembodiments 1 to 17, wherein the halogen consists of Cl, Br, and I.

Embodiment 19. The solid ion conductive material of any one ofembodiments 1 and 4 to 18, wherein the complex metal halide isrepresented by Li3−zMek+X3−z+k, wherein Me comprises a rare earthelement, Zr, or any combination thereof.

Embodiment 20. The solid ion conductive material of any one ofembodiments 1 to 18, wherein the complex metal halide represented by(Li_(1−d)Na_(d))₂Li_(1−z)Me^(k+)X_(3+k−z), wherein Me comprises a rareearth element, Zr, or a combination thereof; and 0≤d<1, −0.95≤z=<0.95.

Embodiment 21. The solid ion conductive material of any one ofembodiments 1 to 20, wherein z≤0.5 or z≤0.3 or z≤0.2.

Embodiment 22. The solid ion conductive material of any one ofembodiments 2 to 21, wherein d≥0.01 or d≥0.05 or d≥0.1.

Embodiment 23. The solid ion conductive material of any one ofembodiments 2 to 22, wherein d≤0.8 or d≤0.5.

Embodiment 24. The solid ion conductive material of any one ofembodiments 1 to 9, wherein the complex metal halide is represented by(Li_((1−d−e)),Na_((d)),M′_((e)))₂Li_((1−z′)) Me³⁺ _((1−u−p−q−r))Me⁴⁺_((u))Me²⁺ _((p))Me⁵⁺ _((q))Me⁶⁺ _((r))Cl_((1−y−w)))_((6+u−p+2q+3r−z′)),wherein:

-   -   0≤d≤1;    -   0≤e<1;    -   −3≤z′<3;    -   M′ includes at least one of K, Rb, Cs;    -   M³⁺ includes a rare-earth element, In, Bi, Sc, Y, Al, Ga or any        combination thereof;    -   Me⁴⁺ is Zr⁴⁺, Hf+, Ti⁴⁺, Sn⁴⁺, Th⁴⁺, Ge⁴⁺ or any combination        thereof;    -   Me²⁺ is Mg²⁺, Zn²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Yb²⁺, Eu²⁺ or any        combination thereof;    -   Me⁵⁺ is Ta⁵⁺, Nb⁵⁺, W⁵⁺, Sb⁵⁺, or any combination thereof;    -   Me⁶⁺ is W⁶⁺, Mo⁶⁺, or any combination thereof;    -   0<=w<=1;    -   0<=y<=1;    -   −0.95<z<0.95;    -   0<=u<0.95;    -   0<=p<0.95;    -   0<=q<0.95; and    -   0<=r<0.95.

Embodiment 25. The solid ion conductive material of embodiment 24,wherein M³⁺ includes Y³⁺, Gd³⁺, In³⁺, Er³⁺, La³⁺, Sc³⁺, or anycombination thereof, wherein M³⁺ consists of Y³⁺, Gd³⁺, In³⁺, Er³⁺,La³⁺, Sc³⁺ or any combination thereof.

Embodiment 26. The solid ion conductive material of embodiment 24 or 25,wherein M⁴⁺ includes Zr⁴⁺, Hf⁴⁺, Ce⁴⁺, or a combination thereof, whereinM⁴⁺ consists Zr⁴⁺, Hf⁴⁺, Ce⁴⁺, or a combination thereof.

Embodiment 27. The solid ion conductive material of any one ofembodiments 24 to 26, wherein:

-   -   p=0;    -   q=0;    -   r=0;    -   u=0; or    -   any combination thereof.

Embodiment 28. The solid ion conductive material of any one ofembodiments 1 to 9 and 24 to 27, wherein k=2 or 3 or 4 or 5.

Embodiment 29. The solid ion conductive material of any one ofembodiments 1 to 28, comprising at least 10 ppm by mass of ammoniumhalide for the total weight of the complex metal halide, at least 100ppm, at least 500 ppm, at least 0.1 wt %, at least 0.3 wt %, at least0.5 wt %, at least 0.8 wt %, or at least 1 wt % of ammonium for theweight of the complex metal halide.

Embodiment 30. The solid ion conductive material of any one ofembodiments 1 to 29, comprising at most 20 wt % of ammonium for thetotal weight of the complex metal halide, at most 15 wt %, at most 10 wt%, at most 8 wt %, at most 5 wt %, or at most 3 wt % of ammonium for theweight of the complex metal halide.

Embodiment 31. The solid ion conductive material of any one ofembodiments 1 to 30, further comprising a total content of simple metalhalide of at most 0.5 wt % for the weight of the complex metal halide,at most 0.3 wt %, at most 0.1 wt %, at most 500 ppm, at most 300 ppm, atmost 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20ppm, or at most 10 ppm for the weight of the complex metal halide.

Embodiment 32. The solid ion conductive material of embodiment 31,comprising at least 0.2 ppm of the simple metal halide for the totalweight of the complex metal halide, at least 0.5 ppm, or at least 1 ppmfor the total weight of the complex metal halide.

Embodiment 33. The solid ion conductive material of embodiment 31 or 32,wherein the simple metal halide comprises alkali metal halide, rareearth halide, or any combination thereof.

Embodiment 34. The ion conductive material of any one of embodiments 1to 33, comprising at least 0.1 ppm by mass of electric charge neutralMe_(x)N_(k) for a weight of the complex metal compound and at most 10ppm by mass of the electric charge neutral Me_(x)N_(k) for the weight ofthe complex metal compound.

Embodiment 35. The ion conductive material of any one of embodiments 1to 34, comprising at least 0.1 ppm by mass of electric charge neutralM_(x)N for a weight of the complex metal compound and at most 10 ppm bymass of the electric charge neutral M_(x)N for the weight of the complexmetal compound.

Embodiment 36. The solid ion conductive material of any one ofembodiments 1 to 35, comprising an ionic conductivity in bulk of atleast 0.001 mS/cm, at least 0.01 mS/cm, at least 0.1 mS/cm, at least 0.4mS/cm, at least 0.8 mS/cm, at least 1.2 mS/cm, at least 1.8 mS/cm, or atleast 2.2 mS/cm.

Embodiment 37. The solid ion conductive material of embodiment 36,comprising an ionic conductivity in bulk of at most 15 mS/cm, at most 13mS/cm, at most 11 mS/cm, 8 mS/cm, at most 7.2 mS/cm, or at most 6.2mS/cm.

Embodiment 38. The solid ion conductive material of any one ofembodiments 1 to 37, wherein the complex metal halide is in a form ofpowder including an average particle size of at least 0.1 microns to 1mm.

Embodiment 39. The solid ion conductive material of any one ofembodiments 1 to 38, wherein the solid conductive material is a singlecrystal or polycrystalline.

Embodiment 40. The solid ion conductive material of embodiment 39,wherein the solid ion conductive material is monocrystalline or anoriented polycrystalline having a crystallographic orientationrepresented by <HKL> or <HKLM>, wherein an ionic conductivity in thecrystallographic orientation of <HKL> or <HKLM> is higher than an ionicconductivity in a different crystallographic orientation.

Embodiment 41. The solid ion conductive material of embodiment 39 or 40,wherein the solid ion conductive material has the crystallographicorientation selected from the group consisting of <100> and <001>.

Embodiment 42. The solid ion conductive material of any one ofembodiments 1 to 41, further comprising Li₄(NH₂)₃Cl, Li₇(NH₂)₆Cl,Li₂Br(NH₂), Li₁₃[NH]₆Cl, LiCl.NH₃, LiBr.4NH₃, or a combination thereof.

Embodiment 43. The solid ion conductive material of any one ofembodiments 1 to 42, further comprising NH₃, NH₄X, or a combinationthereof.

Embodiment 44. A solid-state electrolyte layer, comprising the solid ionconductive material of any one of embodiments 1 to 43.

Embodiment 45. A mixed electron and ion conductive layer comprising thesolid ion conductive material of any one of embodiments 1 to 43, acathode or anode active material, and optionally an electron conductiveadditive.

Embodiment 46. A solid-state lithium battery, comprising the solid-stateelectrolyte layer of embodiment 44.

Embodiment 47. A solid-state lithium battery, comprising the mixedelectron and ion conductive layer of embodiment 45.

Embodiment 48. A solid electrolyte layer, comprising a single-crystalmaterial including a complex metal halide represented byM_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein:

-   -   −3≤z<3;    -   2≤k<6;    -   0≤f≤1;    -   M comprises an alkali metal element;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, a hexavalent metal element, or any combination thereof;        and    -   X comprises a halogen; and    -   wherein the single-crystal material further comprises one of        electric charge neutral Me_(x)N_(k), and M_(x)N wherein x is a        valence of N and k is the valence of Me.

Embodiment 49. A solid electrolyte layer, comprising an orientedcrystalline material having a composition represented byM_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein:

-   -   −3≤z<3;    -   2≤k<6;    -   0≤f≤1;    -   M comprises an alkali metal element;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, a hexavalent metal element, or any combination thereof;        and    -   X comprises a halogen.

Embodiment 50. The solid electrolyte layer of embodiment 49, wherein theoriented crystalline material is an oriented ceramic or an orientedsingle crystal.

Embodiment 51. The solid electrolyte layer of any one of embodiments 48to 50, wherein M comprises at least one of Li and Na.

Embodiment 52. The solid electrolyte layer of any one of embodiments 48to 51, wherein M consists of Li or a combination of Li and at least oneof Na, Cs, Rb, and K.

Embodiment 53. The solid electrolyte layer of any one of embodiments 47to 51, wherein the composition is represented by(Li_(1−d),Na_(d))₂Li_(1−z)Me^(k+)X_(3+k−z), wherein:

-   -   0≤d<1;    -   −0.95≤z<=0.95;    -   2≤k<6;    -   Me comprises a divalent metal element, a trivalent metal        element, a tetravalent metal element, a pentavalent metal        element, hexavalent metal element, or any combination thereof;        and    -   X comprises a halogen.

Embodiment 54. The solid electrolyte layer of any one of embodiments 47to 53 wherein Me comprises a rare earth element and optionally one ormore of alkaline earth metal element, Zn, Zr, Hf, Ti, Sn, Th, Ta, Nb,Mo, W, Sb, In, and Bi.

Embodiment 55. The solid electrolyte layer of any one of embodiments 47to 54, wherein Me comprises Y, Ce, Gd, Er, Zr, La, Yb, In, Mg, or anycombination thereof.

Embodiment 56. The solid electrolyte layer of any one of embodiments 47to 55, wherein X consists of at least one of F, Cl, Br, and I, andoptionally, an anion group including —NH₂ (amide), —(NH)_(0.5) (imide),—OH (hydroxide), —BF₄ groups, or any combination thereof.

Embodiment 57. The solid electrolyte layer of any one of embodiments 47to 55, wherein Me consists of Gd, Ce, Er, Yb, Zr, Y, or any combinationthereof.

Embodiment 58. The solid electrolyte layer of any one of embodiments 47to 55, wherein Me consists of Gd and optionally at least one of Ce, Er,Y, and Zr.

Embodiment 59. The solid electrolyte layer of any one of embodiments 47to 55, wherein Me consists of Yb and Ce.

Embodiment 60. The solid electrolyte layer of any one of embodiments 47to 55, wherein Me consists of Y and optionally at least one of Zr, Ce,Er, and Gd.

Embodiment 61. The solid electrolyte layer of any one of embodiments 47to 60, wherein the halogen consists of one of Cl, Br, I, and F.

Embodiment 62. The solid electrolyte layer of any one of embodiments 47to 61, wherein the halogen consists of at least two or more of Cl, Br,I, and F.

Embodiment 63. The solid electrolyte layer of any one of embodiments 47to 62, wherein the halogen consists of Cl, Br, and I.

Embodiment 64. The solid electrolyte layer of any one of embodiments 47to 63, wherein the composition is represented byLi_(3−z)RE^(k+)X_(3−z+k), wherein RE comprises a rare earth element, Zr,or any combination thereof.

Embodiment 65. The solid electrolyte layer of any one of embodiments 47to 64, wherein k=3 or 4 or 5.

Embodiment 66. The solid electrolyte layer of any one of embodiments 47to 65, wherein the composition is represented(Li_((1−d)),Na_((d)))₂Li_((1−z)) Me³⁺ _((1−u−p−q−r))Me³⁺ _((u))Me²⁺_((p)) Me⁵⁺ _((q))Me⁶⁺_((r))(Cl_((1−y−w))Br_((y))I_((w)))_((6+u−p+2q+3r−z)), wherein:

-   -   0<d<=1;    -   −0.95≤z<=0.95;    -   0<=u<0.95;    -   0<=p<0.95;    -   0<=q<0.95;    -   0<=r<0.95;    -   M³⁺ includes a rare-earth element;    -   Me⁴⁺ is Zr⁴⁺, Hf+, Ti⁴⁺, Sn⁴⁺, Th⁴⁺, or any combination thereof;    -   Me²⁺ is Mg²⁺, Zn²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Yb²⁺, Eu²⁺ or any        combination thereof;    -   Me⁵⁺ is Ta⁵⁺, Nb⁵⁺, W⁵⁺, Sb⁵⁺, or any combination thereof;    -   Me⁶⁺ is W⁶⁺;    -   0<=y<=1; and    -   w<=1.

Embodiment 67. The solid electrolyte layer of embodiment 66, wherein M³⁺includes Y³⁺, Gd³⁺, In³⁺, Er³⁺, La³⁺, or any combination thereof,wherein M³⁺ consists of Y³⁺, Gd³⁺, In³⁺Er³⁺, La³⁺, or any combinationthereof.

Embodiment 68. The solid electrolyte layer of embodiment 66 or 67,wherein M⁴⁺ includes Zr⁴⁺, Ce⁴⁺, or a combination thereof, wherein M⁴⁺consists Zr⁴⁺, Ce⁴⁺, or a combination thereof.

Embodiment 69. The solid electrolyte layer of any one of embodiments 63to 68, wherein:

-   -   p=0;    -   q=0;    -   u=0; or    -   any combination thereof.

Embodiment 70. The solid electrolyte layer of any one of embodiments 47to 69, wherein z≤0.5 or z≤0.3 or z≤0.2.

Embodiment 71. The solid electrolyte layer of any one of embodiments 47to 70, wherein d≥0.01 or d≥0.05 or d≥0.1.

Embodiment 72. The solid electrolyte layer of any one of embodiments 47to 71, wherein d≤0.8 or d≤0.5.

Embodiment 73. The solid electrolyte layer of any one of embodiments 47to 72, wherein the crystalline material comprising a total content of animpurity of at most 0.5 wt %, at most 0.2 wt %, at most 0.1 wt %, atmost 500 ppm, at most 200 ppm, at most 100 ppm, or at most 50 ppm forthe total weight of the crystalline material.

Embodiment 74. The solid electrolyte layer of embodiment 73, wherein theimpurity comprises a simple metal halide including a rare earth halide,an alkali halide, electric charge neutral Me_(x)N_(k), electric chargeneutral M_(x)N, or any combination thereof.

Embodiment 75. The solid electrolyte layer of any one of embodiments 47to 74, wherein the crystalline material comprising a total content of animpurity of at least 2 ppm for a weight of the complex metal halide, atleast 5 ppm, or at least 10 ppm for the weight of the crystallinematerial.

Embodiment 76. The solid electrolyte layer of any one of embodiments 47to 75, wherein the crystalline material comprises at least 0.1 ppm bymass and at most 10 ppm by mass of electric charge neutral Me_(x)N_(k)for a weight of the complex metal halide.

Embodiment 77. The solid electrolyte layer of any one of embodiments 47to 76, wherein the crystalline material comprises at least 0.1 ppm bymass and at most 10 ppm by mass of electric charge neutral M_(x)N for aweight of the complex metal halide.

Embodiment 78. The solid electrolyte layer of any one of embodiments 47to 77, wherein the crystalline material comprises Li₄(NH₂)₃Cl,Li₇(NH₂)₆Cl, Li₂Br(NH₂), Li₁₃[NH]₆Cl, LiCl.NH₃, LiBr.4NH₃, or acombination thereof.

Embodiment 79. The solid electrolyte layer of any one of embodiments 47to 78, wherein the crystalline material comprises NH₃, NH₄X, or acombination thereof.

Embodiment 80. The solid electrolyte layer of any one of embodiments 47to 79, wherein the crystalline material comprises a bulk ionicconductivity of at least 0.01 mS/cm, at least 0.1 mS/cm, at least 0.2mS/cm, at least 0.4 mS/cm, at least 0.5 mS/cm at least 0.8 mS/cm, atleast 1.2 mS/cm, at least 1.8 mS/cm, or at least 2.2 mS/cm at 22° C. andactivation energy in the range 0.01 eV and 0.5 eV, or wherein thecrystalline material comprises an ionic conductivity of at most 15mS/cm, at most 11 mS/cm, at most 9 mS/cm, at most 8 mS/cm, at most 7.2mS/cm, or at most 6.2 mS/cm.

Embodiment 81. The solid electrolyte layer of any one of embodiments 1to 80, comprising a thickness, wherein the thickness extends in acrystallography orientation of <HKL> or <HKLM>, wherein an ionicconductivity in the crystallographic orientation of <HKL> or <HKLM> ishigher than an ionic conductivity in a different crystallographicorientation.

Embodiment 82. The solid electrolyte layer of embodiment 81, wherein thecrystallography direction is selected from the group consisting of<100>, <001>, and <010>.

Embodiment 83. The solid electrolyte layer of any one of embodiments 47to 82, wherein the single crystal material is in a form of a sheet.

Embodiment 84. The solid electrolyte layer of any one of embodiments 1to 83, comprising a thickness from 5 microns to 500 microns.

Embodiment 85. A process of forming a solid ion conductive material,comprising:

-   -   forming (NH₄)_(n)Me^(k+)X_(3+k), wherein forming        (NH₄)_(n)Me^(k+)X_(3+k) comprises chemically substituting        moisture in a hydrated salt-containing REX₃ with NH₄X, wherein        n>0; Me comprises a rare earth element, Zr, or a combination        thereof; and X is one or more halogen.

Embodiment 86. The process of embodiment 85, further comprisingperforming a solid-state reaction of (NH₄)_(n)Me^(k+)X_(3+k) and MX,wherein M comprises an alkali metal.

Embodiment 87. The process of embodiment 85 or 86, further comprisingdecomposing (NH₄)_(n)Me^(k+)X3+k.

Embodiment 88. The process of any one of embodiments 85 to 87, furthercomprising forming the solid ion conductive material including a complexmetal halide represented by M_(3−z)Me^(k+)X_(3−z+k), wherein −3≤z<3;2≤k<6; M comprises at least one of Li and Na, wherein the solid ionconductive material comprises a total content of an impurity of at most0.5 wt % for the weight of the solid ion conductive material.

Embodiment 89. The process of embodiment 88, wherein the impuritycomprises Me^(k+)X_(k), MX, or a combination thereof.

Embodiment 90. The process of any one of embodiments 86 to 89, furthercomprising growing a crystal including the complex metal halide.

Embodiment 91. The process of any one of embodiments 85 to 90, furthercomprising forming an oriented crystalline material including acrystallographic orientation selected from the group consisting of<010>, <100>, and <001>.

Embodiment 92. The process of embodiment 90 or 91, further comprisinggrowing the crystal from a melt, wherein the melt comprises the complexmetal halide and optionally a dopant material.

Embodiment 93. The process of any one of embodiments 85 to 92, whereinthe ion conductive material is a polycrystalline material.

Embodiment 94. The process of any one of embodiments 85 to 93, whereinthe ion conductive material comprises a content of electric chargeneutral Me_(x)N_(k) of at most 0.5 wt % for a weight of the ionconductive material;

Embodiment 95. The process of any one of embodiments 85 to 94, whereinthe ion conductive material comprises a content of Me_(x)N_(k) of atleast 0.1 ppm and at most 10 ppm by mass for a weight of the ionconductive material.

Embodiment 96. The process of any one of embodiments 85 to 95, whereinthe ion conductive material comprises a content of electric chargeneutral M_(x)N of at most 0.5 wt % for a weight of the ion conductivematerial.

Embodiment 97. The process of any one of embodiments 85 to 96, whereinthe ion conductive material comprises a content of electric chargeneutral M_(x)N of at least 0.1 ppm and at most 10 ppm by mass for aweight of the ion conductive material.

Embodiment 98. The process of any one of embodiments 85 to 97, whereinthe ion conductive material further comprising forming Li₄(NH₂)₃Cl,Li₇(NH₂)₆Cl, Li₂Br(NH₂), Li₁₃[NH]₆Cl, LiCl.NH₃, LiBr.4NH₃, or acombination thereof.

Embodiment 99. The process of any one of embodiments 85 to 97, whereinthe ion conductive material further comprises NH₃, NH₄X, or acombination thereof.

EXAMPLES Example 1

Samples 1 to 30 were formed having the composition noted in Table 1.Content of impurity of simple metal halide is included in Table 1 andthe phase for each impurity was detected by XRD analysis coupled withRietveld refinements for quantitative analysis through the presence ofcharacteristic diffraction peaks corresponding to the parasitic phases.

All Samples had a content of metal nitride of up to 10 ppm. Samples 1,2, 4 to 6, 15, 17, and 30 were pressed ceramics pellets and heated underdry inert conditions. The pellets were formed according to the humidammonium route described in embodiments herein except Sample 6. Sample 6was formed by using the one-step forming process described inembodiments herein. The pellets are 5 to 13 mm (diameter) by 0.5 to 4 mm(thickness). Samples 8 to 14 and 18 to 29 are sliced from singlecrystals formed according to embodiments herein. For the formation ofSamples 20, 21, and 23, LiCl, LiBr, and LiI salts were also usedrespectively, as the additives for the starting material charges for thecrystal growth of anionically substituted compounds.

Ionic conductivity of the samples was determined using anelectrochemical impedance spectroscopy method with gold blockingelectrodes under the condition of an AC frequency of 3 MHz-10 Hz and 10to 50 mV of peak-to-peak sinusoidal AC voltage signal at roomtemperature (approximately 22° C.).

The ion conductivity of bulk grains in Samples 1, 2, 4 to 6, 15, 17, and30 was included in Table 1. The conductivity contribution from bulkgrains could be separated from grains boundary and the electrode contactbecause the bulk grain conductivity features appear at the highestfrequencies and are associated with the lowest value of double-layercapacitance.

For Sample 3, neither direction A and direction B corresponds to theorientations that demonstrates maximal thermal and/or ionicconductivities of Li₃YCl₆. Slicing in direction A resulted in a ceramicsample having grains in random crystallographic orientations. DirectionA can be determined by vector a, wherein a=α*<100>+β*<010>, and wherein−1.0<α<1.0 and −1.0<β<1.0. Slicing in direction B resulted in anoriented ceramic sample having the orientation close to <001>crystallographic orientation.

TABLE 1 No Measured Ionic Impurities example Composition Synthesismethod Conductivity, mS/cm concentration 1 Li₃YCl₆ Ceramics form 0.2 4.2wt % LiCl + Humid ammonium chloride + 2.5 wt % YCl₃ sublimation 2Li₃YCl₆ Ceramics form 0.4 Not detectable, Humid ammonium chloride +below ~0.2 wt % sublimation + grinding + reactive sublimation 3 Li₃YCl₆Crystal growth of dense block 0.53 (direction A) Not detectable,composed of mm-size single crystals. 0.96 (direction B) below ~0.2 wt %Block sliced along two directions. 4 Li₃YBr₆ Ceramics form 0.7 5.4 wt %LiBr + Humid ammonium bromide + 3.1 wt % YBr₃ sublimation 5 Li₃YBr₆Ceramics form 1.5 Not detectable, Humid ammonium chloride + below ~0.2wt % sublimation + grinding + reactive sublimation 6 Li₃YBr₆ Ceramicsform 0.47 6.7 wt % LiBr + Reaction at dry condition with 3.5 wt % YBr₃ammonium bromide followed by sublimation ammonium bromide 7 Li₃YBr₆Crystal growth of finger-sized single 1.8 Not detectable, Orientationscrystal ingot 1.3 below ~0.2 wt % <100> 3.1 <010> <001> 8 (Na_(0.1),Li_(0.9))₂LiYCl₆ Crystal growth 0.7 Not detectable, below ~0.2 wt % 9(Na_(0.1), Li_(0.9))₂LiYBr₆ Crystal growth 0.9 Not detectable, below~0.2 wt % 10 Li_(2.8)YCl_(5.8) Crystal growth 0.95 Not detectable, below~0.2 wt % 11 Li_(2.8)YBr_(5.8) Crystal growth 1.7 Not detectable, below~0.2 wt % 12 Li₃Y_(0.95)Ce_(0.05)Cl₆ Crystal growth 0.5 Not detectable,below ~0.2 wt % 13 Li₃Y_(0.95)Ce_(0.05)Br₆ Crystal growth 1.5 Notdetectable, below ~0.2 wt % 14 Li₃Y_(0.8)Gd_(0.2)Br₆ Crystal growth 1.6Not detectable, below ~0.2 wt % 15 Li₃GdBr₆ Ceramics form powder formedby 1.1 4.7 wt % LiBr Humid ammonium bromide + sublimation + grinding 16Li₃GdBr₆ Crystal growth 3.5 Not detectable, below ~0.2 wt % 17 Li₃GdCl₆Ceramics form 0.9 3.8% LiCl + Humid ammonium chloride + 1.5% GdCl₃sublimation + grinding 18 Li₃GdCl₆ Crystal growth 1.8 Not detectable,below ~0.2 wt % 19 Li₃Y_(0.7)Er_(0.3)Br₆ Crystal growth 1.3 Notdetectable, below ~0.2 wt % 20 (Li_(0.9,)Na_(0.1))₂LiY_(0.8)Zr_(0.2)Cl_(6.2) Crystal growth 3.1 Not detectable,below ~0.2 wt % 21 (Li_(0.7,) Na_(0.3))₂LiY_(0.7)Zr_(0.3)Br_(6.3)Crystal growth 2.8 Not detectable, below ~0.2 wt % 22Li₃YBr_(4.5)Cl_(1.5) Crystal growth 1.1 Not detectable, below ~0.2 wt %23 Li₃YBr_(5.2)l_(0.8) Crystal growth 2.2 Not detectable, below ~0.2 wt% 24 Cs₂LiLa_(0.98)Ce_(0.02)Br₆ Crystal growth 0.1 Not detectable, below~0.2 wt % 25 Cs₂LiY_(0.98)Ce_(0.02)Cl₆ Crystal growth 0.04 Notdetectable, below ~0.2 wt % 26 Li₃YbBr₆ Crystal growth 0.8 Notdetectable, below ~0.2 wt % 27 Li₃YbCl₆ Crystal growth 0.7 Notdetectable, below ~0.2 wt % 28 Li₃Yb_(0.98)Ce_(0.02)Br₆ Crystal growth0.85 Not detectable, below ~0.2 wt % 29 Li₃Yb_(0.97)Ce_(0.03)Cl₆ Crystalgrowth 0.75 Not detectable, below ~0.2 wt % 30Li₃Y_(0.23)In_(0.11)Zr_(0.33)Mg_(0.33)Cl₆ Ceramics form 0.5 5.4 wt %LiBr + Humid ammonium chloride + 2.6 wt % MgCl₃ sublimation + grinding

Example 2

A poly-crystalline block of Li₃YB₆ was formed having a cylindrical shapeand a dimension of 7 cm×10 cm. The block is composed of densely packedsingle crystals having mm to cm sizes and arranged in a mica-likelayered orientation. The bulk ion conductivity was measured on smallpieces broken-off from the center of the block. The pieces were polishedinto approximately 0.7 mm thick parallelized samples and the impedancewas measured in the same manner as described in Example 1. It wasapproximately 0.5 or 2.5 mS/cm depending on the direction of the samplechosen. XRD analysis confirmed that the two samples had differentcrystallographic orientations.

The first sample with grains mainly (more than 80%) orientedapproximately along the crystallographic direction <100> having also themaximum thermal conductivity and showed higher ionic conductivity. Thesecond sample is demonstrating randomly oriented grains withcrystallographic orientations belonging to the plane orthogonal to the<001> direction;

Example 3

The crystalline pure material was milled using an automated mortar andpestle grinder. This low energy milling preserves the purity of thematerials. The same material was milled in high energy ball milling, anda partial decomposition of the pure material was observed, as indicatedby the appearance of small signatures of simple halides in the XRDanalysis. The conductivity of the decomposed powder was lower than thepure powder or the oriented crystal/ceramic.

Example 4

Impurities concentration, No Measured Ionic non-reacted or SampleComposition Synthesis method Conductivity, mS/cm decomposed C1.B Li₃YCl₆Ball milling at room 0.15 11.5 wt % LiCl + temperature for 24 hrs, with8.0 wt % YCl₃ starting materials of dry LiCl and anhydrous YCl₃ atstoichiometric proportion C4.B Li₃YBr₆ Ball milling at room 0.6 10.5 wt% LiBr + temperature for 24 hrs, using 7.5 wt % YBr₃ starting materialsof dry LiBr and anhydrous YBr₃ at stoichiometric proportion C1.C Li₃YCl₆Solid-state reaction with 0.05 14.5 wt % LiCl + NH₄Cl and Sublimation at7 wt % YOCl + 450° C. using starting 3.5 wt % YCl3 materials of Li₂CO₃and Y₂O₃ mixed at stoichiometric proportion of 3*Li/Y being 1 and NH₄Clin excess C4.C Li₃YBr₆ Solid-state reaction with 0.45 13 wt % LiBr +NH₄Br and Sublimation at 6 wt % YOBr + 450° C., using starting 3 wt %YBr materials Li₂CO₃ and Y₂O₃ at 3*Li/Y being 1 stoichiometricproportion and NH₄Br in excess

It is noted the high energy ball milling synthesis can generate inparallel the reactions of synthesis but also the decomposition of theprincipal complex metal halide phase. Comparing to process ofembodiments herein, the high energy ball milling synthesis can generatesignificantly higher contents of simple compounds, such as LiX and YX₃,that are present as the impurities in the vicinity of principal Li₃YX₆phase.

It is also noted a single phase of Li₃YX₆ may not be synthesized whenstarting from oxides (Y₂O₃) or carbonate materials (Li₂CO₃) with theaddition of ammonium halide in the solid-state reaction at 1 baratmospheric pressure. At least two chemical reactions can take place forthe rare-earth metal (i.e., Y in the example of Li₃YX₆) conversion intohalide compounds. One principal reaction can result in YX₃ synthesisthat can further react to form the Li₃YX₆ phase. The second reaction canresult in the formation of YOX. YOX is a stable compound and can bepresent as an impurity in the final product of Li₃YX₆.

Example 5

Additional samples were formed. Sample 35 was synthesized by using astoichiometric mixture of LiBr and YBr₃ compounds in welded quartzampoule under vacuum with heat up to 650° C. After the reaction mixturemelted, a soak time of up to an hour at 650° C. was applied to ensurereaction products are dissolved in the self flux. Then the temperatureof the quartz ampoule was dropped down promptly (in 2-3 minutes) to 400°C. to help minimize partial decompositions of the incongruent Li₃YBr₆phase. Then the temperature of the quartz ampoule was decreasedprogressively to room temperature at a rate of 50-100° C./hour.

Samples 36 and 37 were synthesized according to embodiments hereinvoluntarily keeping ammonium. The quantity of residual ammonium wasestimated by posterior overheating of a compound up to the meltingtemperature permitting to fully sublimate ammonium halide from thecharge. Ionic conductivity in the bulk of the samples was measured in asimilar manner as described in Example 1.

Ionic Sample Compound conductivity, mS/cm 35 Li₃YBr₆ 1.6 36 Li₃YBr₆ +0.001 NH₄Br 1.9 37 Li₃YBr₆ + 0.2 NH₄Br 2.5

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims. Reference herein to a materialincluding one or more components may be interpreted to include at leastone embodiment wherein the material consists essentially of the one ormore components identified. The term “consisting essentially” will beinterpreted to include a composition including those materialsidentified and excluding all other materials except in minority contents(e.g., impurity contents), which do not significantly alter theproperties of the material. Additionally, or in the alternative, incertain non-limiting embodiments, any of the compositions identifiedherein may be essentially free of materials that are not expresslydisclosed. The embodiments herein include a range of contents forcertain components within a material, and it will be appreciated thatthe contents of the components within a given material total 100%.

The specification and illustrations of the embodiments described hereinare intended to provide a general understanding of the structure of thevarious embodiments. The specification and illustrations are notintended to serve as an exhaustive and comprehensive description of allof the elements and features of apparatus and systems that use thestructures or methods described herein. Separate embodiments may also beprovided in combination in a single embodiment, and conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges includes each and everyvalue within that range. Many other embodiments may be apparent toskilled artisans only after reading this specification. Otherembodiments may be used and derived from the disclosure, such that astructural substitution, logical substitution, or another change may bemade without departing from the scope of the disclosure. Accordingly,the disclosure is to be regarded as illustrative rather thanrestrictive.

What is claimed is:
 1. A solid ion conductive material, comprising acomplex metal halide material represented byM_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein: −3≤z<3; 2≤k<6; 0≤f≤1; Mcomprises an alkali metal element; and Me comprises a divalent metalelement, a trivalent metal element, a tetravalent metal element, apentavalent metal element, a hexavalent metal element, or anycombination thereof; and X comprises a halogen, wherein the complexmetal halide material comprises at least one of electric charge neutralMe_(x)N_(k) or M_(x)N, wherein x is a valence of N and k is the valenceof Me.
 2. The solid ion conductive material of claim 1, wherein thecomplex metal halide material is represented by(Li_(1−d−e),Na_(d),M′_(e))₂(Me^(k+))_(f)X_(3+k*f−z′), wherein: 0≤d≤1;0≤e<1; 0<=(d+e)<=1 −1≤z′<=1; M consists of at least one of Li, Na, andM′; and M′ consists of at least one of K, Rb, and Cs.
 3. The solid ionconductive material of claim 1, wherein z is between −0.95 and 0.95 andM consists of Na and Li.
 4. The solid ion conductive material of claim1, wherein Me comprises one or more of a rare earth element, alkalineearth metal element, 3d transition metal, Zn, Zr, Hf, Ti, Sn, Th, Ge,Ta, Nb, Mo, W, Sb, In, Bi, Al, Ga, Fe or any combination thereof.
 5. Thesolid ion conductive material of claim 1, wherein Me comprises Y, Ce,Gd, Er, Zr, La, Sn, Yb, In, Mg, Zn, or any combination thereof.
 6. Thesolid ion conductive material of claim 1, wherein X consists of at leastone of F, Cl, Br, and I, and optionally, an anion group including —NH₂(amide), —(NH)_(0.5) (imide), —OH (hydroxide), —BH₄ (borohydride), —BF₄groups, or any combination thereof.
 7. The solid ion conductive materialof claim 1, wherein the complex metal halide represented by(Li_(1−d)Na_(d))₂Li_(1−z)Me^(k+)X_(3+k−z), wherein Me comprises a rareearth element, Zn, Sn, In, Zr, or a combination thereof; and 0<d<1,−0.95<z=<0.95.
 8. The solid ion conductive material of claim 1, whereinz≤0.5.
 9. The solid ion conductive material of claim 1, wherein d≥0.01,and wherein d≤0.8.
 10. The solid ion conductive material of claim 1,wherein the complex metal halide material comprises a single crystal, aceramic, or a combination thereof.
 11. A solid ion conductive material,comprising an oriented ceramic material comprising a complex metalhalide material represented by M_(3−z)(Me^(k+))_(f)X_(3−z+k*f), wherein:−3≤z<3; 2≤k<6; 0≤f≤1; M comprises an alkali metal element including Li;and Me comprises a divalent metal element, a trivalent metal element, atetravalent metal element, a pentavalent metal element, a hexavalentmetal element, or any combination thereof; and X comprises a halogen.12. The solid ion conductive material of claim 11, wherein the complexmetal halide material is represented by(Li_((1−d−e)),Na_((d))M′_((e)))₂Li_((1-z′))Me³⁺ _((1−u−p−q−r))Me⁴⁺_((u))Me²⁺ _((p))Me⁵⁺ _((u))Me⁶⁺_((r))(Cl_((1−y−w))Br_((y))I_((w)))_((6+u−p+2q+3r−z′)), wherein: 0≤d≤1;0≤e<1; 0<=(d+e)<1; −1≤z′<1; M′ includes at least one of K, Rb, Cs; M³⁺includes a rare-earth element, In, Bi, Sc, Y, Al, Ga, or any combinationthereof; Me⁴⁺ is Zr⁴⁺, Hf+, Ti⁴⁺, Sn⁴⁺, Th⁴⁺, Ge⁴⁺ or any combinationthereof; Me²⁺ is Mg²⁺, Zn²⁺, Sr²⁺, Ba²⁺, Yb²⁺, Eu²⁺ or any combinationthereof; Me⁵⁺ is Ta⁵⁺, Nb⁵⁺, W⁵⁺, Sb⁵⁺, or any combination thereof; Me⁶⁺is W⁶⁺, Me⁶⁺, or any combination thereof; 0<=w<=1; 0<=y<=1; 0<=(y+w)<=1;−0.95<z<0.95; 0<=u<0.95; 0<=p<0.95; 0<=q<0.95; 0<=r<0.95; and0<=(u+p+q+r)<=1.
 13. The solid ion conductive material of claim 12,wherein M³⁺ includes Y³⁺, Gd³⁺, In³⁺, Er³⁺, La³⁺, Sc³⁺, or anycombination thereof.
 14. The solid ion conductive material of claim 12,wherein M⁴⁺ includes Zr⁴⁺, Hf+, Ce⁴⁺, or a combination thereof, whereinM⁴⁺ consists Zr⁴⁺, Hf⁴⁺, Ce⁴⁺, or a combination thereof.
 15. The solidion conductive material of claim 12, wherein: p=0; q=0; r=0; u=0; or anycombination thereof.
 16. The solid ion conductive material of claim 12,wherein the complex metal halide comprises a total content of simplemetal halide of at most 10 wt % for a weight of the complex metalhalide.
 17. The solid ion conductive material of claim 16, wherein thesimple metal halide comprises alkali metal halide, rare earth halide, orany combination thereof.
 18. The solid ion conductive material of claim12, wherein the oriented complex metal halide material has acrystallographic orientation represented by <HKL> or <HKLM>, wherein anionic conductivity in the crystallographic orientation of <HKL> or<HKLM> is higher than an ionic conductivity in a differentcrystallographic orientation.
 19. A solid-state electrolyte layer,comprising the solid ion conductive material of claim
 1. 20. A processof forming a solid ion conductive material, comprising: forming(NH₄)_(n)Me^(k+)X_(3+k), wherein forming (NH₄)_(a)Me^(k+)X_(3+k)comprises chemically substituting moisture in a hydrated salt containingREX₃ with NH₄X, wherein n>0; Me comprises a rare earth element, Zr, or acombination thereof; and X is one or more halogen.